Developing mechanism for heat developable light sensitive copy paper



April 1969 MINORU UMAHASHI ETAL. 3,436,523

DEVELOPING MECHANISM FOR HEAT DEVELOPABLE LIGHT SENSITIVE COPY PAPER Filed July 19, 1967 INVENTORS' 7mm WWW United States Patent 3,436,523 DEVELOPING MECHANISM FOR HEAT DEVELOP- ABLE LIGHT SENSITIVE COPY PAPER Minoru Umahashi, Tokyo, and Hitoshi Yarnakawa, Fujisawa, Japan, assignors to Kabushiki Kaisha Ricoh, Tokyo, Japan, a corporation of Japan Filed July 19, 1967, Ser. No. 654,476 Claims priority, application Japan, July 27, 1966, ll/71,145 Int. Cl. Hb 3/44 US. Cl. 219-216 5 Claims ABSTRACT OF THE DISCLOSURE Brief summary of the invention The present invention has to do with the construction of a special cylindrical mechanism for heat development of light sensitive copy paper in place of a continuous peripheral cylindrical surface. The path the copy paper travels is made up of a series of annular units surrounding an axially arranged heat generator. These units are spaced apart in parallel planes at right angles to the axis of the generator and are secured together by longitudinal rods so that the periphery of the units form a cylindrical surface. Cooperating rollers create a path for the paper so that it travels around the periphery of the annular units where it is subjected to the heat of the axially disposed heat generator.

Brief description of the accompanying drawing FIG. 1 is a cross section of a developing mechanism illustrating one embodiment of this utility model.

FIG. 2 is a front view of a rotary wheel unit only used in the above embodiment.

Detailed description of this utility model This utility model relates to a thermal developing mechanism whereby a light exposed copy paper is thermally developed.

The thermal developing mechanism known in the art employs a rotary heating cylinder and a heat-proof copy paper holding canvas which is pressed against said cylinder in a stationary status relative thereto. When a thermally developable light sensitive copy paper is fed between said cylinder and the canvas, the copy paper is adapted to be exposed by heat of said cylinder while traveling around the latter. There are, however, numerous drawbacks with this type of developing mechanism. For example, when a light exposed copy paper is fed between the heating cylinder and the copy paper holding canvas, the copy paper generates steam which causes wrinkles thereon. To describe this process in further detail, when a light exposed copy paper is inserted, for thermal development of a latent image thereon, at a copy paper insertion mouth formed with the heating cylinder and the aforesaid canvas, the leading edge of the thermally developable light sensitive copy paper first comes in contact with the heating cylinder. The leading portion of the copy paper thereupon violently generates, as it is Cir 3,436,523 Patented Apr. 1, 1969 abruptly heated by the heating cylinder, considerable amount of steam for a given unit of time. The steam thus generated tends to find its way out through said copy paper insertion mouth, whereupon the liquefied steam moistens the following area of the copy paper. As this cycle is repeated, while the copy paper is being fed into the copy paper insertion mouth, the wet area of the copy paper gradually moves, absorbing increasing moisture, towards the bottom edge of the copy paper. This causes wrinkles or stains by the time the bottom end of the copy paper proceeds between the heating cylinder and the copy paper holding canvas.

The foregoing drawback is obviously caused, partly by the fact that the copy paper is brought into contact directly with a heating cylinder the temperature of which is approximately C., and partly because the steam generated from the copy paper has no outlet except said copy paper insertion mouth.

Another drawback of the known developing mechanism carrying rotary heating cylinder and a copy paper holding canvas pressed against said cylinder, is that the steam generated from the copy paper causes the friction force between the copy paper and the copy paper holding canvas to increase, which, in turn, affects the copy paper transporting function of the heating cylinder, hampering smooth transportation of the copy paper.

Furthermore, with the known mechanism in which the thermally developable copy paper is adapted to be heated by the circumference of the heating cylinder, the desired development of the copy paper can not take place until the heat generator incorporated in the heating cylinder heats up the latter to a predetermined temperature.

The primary object of this utility model, therefore, is to provide a heat-developing mechanism whereby all of the above-mentioned drawbacks of the conventional mechanisms can be removed. For a fuller understanding of the nature and the objects of this utility model, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein:

Numeral 1 represents a cylindrical heat generator, 2 illustrates wheel units arranged and fixed, at equal intervals, on rods 4 which are fixed, at its ends, to a pair of ring-shape end plate 3a and 3b. 5, 6 and 7 respectively represent rotary copy paper feeding rollers pressed against said wheel units. 8 is a cover plate encircling said wheel units 2 and feed rollers 5, 6 and 7, forming, with its inner surface, a copy paper path 9 between said wheel units 2. 10 illustrates copy paper feeding mouth, 11 a takeout opening, 12 a heat preserving member provided on the outer surface of said cover plate 8, and 13 a light sensitive thermally developable copy paper.

Said pair of end plates 3a and 3b are rotatably mounted on side walls 14a and 14b of the developing mechanism and, upon rotation, by the action of a suitable driving mechanism, of a gear 15 provided outside of either one of said end plates, said end plates and the wheel units 2 are adapted to rotate in the direction of the arrow, as shown in FIG. 1, thereby guiding the leading edge of the copy paper inserted from said insertion mouth 10 into the copy paper path 9. The copy paper thus fed into the copy paper path 9 is then developed by the radiant heat of the heat generator 1 and delivered to the take-out opening 11.

It will therefore been seen that, according to the present utility model, the copy paper is not heated suddenly in direct contact with the circumference of a heating cylinder or the like which means that there will be no steam generated which moistens the copy paper. If any steam is generated, the proposed mechanism of the present utility model is so designed that such steam will be dispersed without any effect on the copy paper. Furthermore, smooth transportation of the copy paper and immediate availability of developing condition after starting the copying machine are ensured.

We claim:

1. A developing mechanism for developing thermally developable light sensitive copy paper, comprising a fixedly secured cylindrical heat generator, plurality of rotatable wheel units which are provided in spaced apart relationship around said heat generator and transfixed with rods which are disposed parallel with said heat generator, the circumference of said wheel units being pressed, at suitable positions, with a plurality of copy paper feeding rollers provided parallel with each other and with said heat generator, said circumference forming a copy paper path having a copy paper feeding mouth and a copy paper delivering opening, said copy paper path being covered with a heat preserving member.

2. A cylindrical developing mechanism for developing thermally developable light sensitive copy paper comprising an elongated heat generator, a plurality of annular units arranged around said generator in parallel spaced apart planes with said generator in axial relationship to said units, longitudinally arranged and peripherally spaced rods joining said units into a cylindrical arrangement, and a plurality of longitudinally arranged paper feeding rollers adjacent the periphery of said units to form a copy paper path around the periphery of said units for exposure to said axially positioned heat generator.

3. A cylindrical developing mechanism for developing thermally developable light sensitive copy paper, comprising an axially disposed heat generator, a plurality of parallel annular units arranged around said generator and joined in axially spaced apart relation by longitudinally arranged rods parallel to said generator, a plurality of copy paper feeding rollers arranged in contact with the periphery of said annular units and parallel to said generator, and the circumference of said annular units and said rollers forming a copy paper path having a copy paper feeding mouth and a copy paper delivering opening.

4. A cylindrical developing mechanism for developing thermally developable light sensitive copy paper comprising an elongated heat generator, a plurality of annular units arranged around said generator in parallel spaced apart planes With said generator in axial relationship to said units, and a plurality of longitudinally arranged paper feeding rollers adjacent the periphery of said units to form a copy paper path around the periphery of said units for exposure to said axially positioned heat generator.

5. A cylindrical developing mechanism for developing thermally developable light sensitive copy paper comprising an elongated heat generator, a plurality of annular units arranged around said generator in parallel spaced apart planes with said generator in axial relationship to said units, supporting means radially spaced from said generator for supporting said units so that the peripheral surface of said units forms a cylindrical plane having the generator as an axis, and a plurality of longitudinally arranged paper feeding rollers adjacent the periphery of said units to form a copy paper path around the periphery of said units for exposure to said axially positioned heat generator.

References Cited UNITED STATES PATENTS 1,539,952 6/1925 Pohl 118-202 X 1,615,778 1/1927 Walstead 29125 X 2,232,765 2/1941 Bliven 19337 3,224,355 12/ 1965 Thomiszer 77.5 3,280,717 10/1966 Bungay 21'9216 X 3,333,088 7/1967 Verbeek 219388 X RICHARD M. WOODS, Primary Examiner. C. L. ALBRTTTON, Assistant Examiner.

US. Cl. X.R. 

